1. The Field of the Invention
The field of the invention is automatic engine control systems; more particularly, such systems which automatically activate the start means and the shutdown of an internal combustion engine, monitor the engine for fault conditions which may cause damage to the engine, and when such fault conditions occur, automatically activate the shutdown of the engine and indicate the existing fault.
2. Description of the Prior Art
There are numerous engine control systems in the prior art. Most control units automatically control the start of the engine and automatically cause the engine to shutdown if ignition does not occur within a specified time. The systems have engine sensors that are sensitive to various fault conditions which may damage the engine; and will cause the engine to shutdown in the event that a fault condition is detected.
Earlier control units were electrically operated by mechanical switches and relays. These systems presented problems of reliability after extended periods of use. They were susceptible to malfunction due to the effects of the vibration of the engine and other external factors. Their timing circuitry was not reliable and the circuits were not sensitive to small variations in the operating signals. The units were often quite expensive
More recent systems have taken advantage of solid state circuitry. These systems are more compact, have reliable timing circuitry, and are less susceptible to external factors. However, for these systems to operate properly they must generally be in an energized state during the entire time that they are in operation because a trickle current is required in order to maintain the various solid state components in a standby state.
As a result of the necessity that the solid state components be constantly maintained in an energized state, these systems are susceptible to false triggers due to voltage transients. The extended exposure of the solid state components to surges and interruptions in power causes a higher incidence of component failure. Solid state components are significantly more susceptible to certain types of abuse than are relays. In addition, because a trickle current must be constantly maintained, the lifetime of the system itself is diminished.
Solid state systems generally utilize transistors or SCR's to latch various signals and to control the start up and the shutdown of the engine. There are several disadvantages with maintaining such signals through solid state components. Momentary surges and interruptions in power can initiate false triggers and release latched conditions. When solid state components are used for this purpose they must be constantly maintained in an energized state, thus their expected useful lives are diminished.
Solid state systems in the prior art are also often susceptible to damage caused by miswiring of the system to the battery and the various engine controls. This is because the requirement that these components be constantly maintained in an energized state causes them to be exposed to damage in the event of miswiring.
Automatic engine control systems have generally not integrated a means for controlling the operation of the battery charger of the controlled engine. Certain systems which have done so that only energized the charger during the normal operation of the engine.